Michael Schumacher has already shed three kilograms as he pushes for race fitness prior to his formula one return in Spain later this month.

Michael Schumacher has already shed three kilograms as he pushes for race fitness prior to his formula one return in Spain later this month.

"I already lost three kilograms even if it is also important to me to build up muscles," the 40-year-old German said on his official website michael-schumacher.de.

He has done some testing and motorcycle racing and plenty of karting since retiring from F1, but his last grand prix was in Brazil at the end of 2006.

Schumacher, replacing the injured Felipe Massa at Ferrari probably for the remainder of the 2009 season, ran nearly 70 laps in a two-year old F2007 last Friday at Mugello and it is believed he will be back in action in the car this week.

"All in all, the practice works pretty well," he explained. "I only have to admit that my neck pinches a bit.

"We have to get a grip on that as health has priority -- that's the clear arrangement made with Ferrari and, by the way, with my wife, too," said Schumacher.